Pseudoholomorphic maps between almost complex manifolds #
A map u : M → M' between manifolds carrying smooth almost complex structures j and J is
pseudoholomorphic (a J-holomorphic curve, when M is a Riemann surface) at x when it has a
manifold Fréchet derivative there which intertwines the two structures:
du_x ∘ j(x) = J(u x) ∘ du_x. This is the nonlinear Cauchy--Riemann equation, here with a target
structure that genuinely varies over a manifold rather than over a normed space.
Why the name is not IsJHolomorphic #
TauCeti.IsJHolomorphic is already the varying-structure predicate for maps between normed
spaces (TauCeti/Geometry/Symplectic/JHolomorphic/Varying.lean), which is the local coordinate
model of this one, and TauCeti.IsConstStructureJHolomorphic is the flat, single-structure model
below that. The manifold-level predicate therefore takes the equally standard name
pseudoholomorphic (Gromov's term, used interchangeably with J-holomorphic in
McDuff--Salamon). isPseudoholomorphicAt_iff_isJHolomorphicAt below identifies the two on a
model vector space, so the naming records a difference of setting, not of mathematics.
Main declarations #
TauCeti.IsPseudoholomorphicWithinAt,TauCeti.IsPseudoholomorphicAt: the Cauchy--Riemann equation for the derivative within a set, respectively at a point.TauCeti.IsPseudoholomorphicOn,TauCeti.IsPseudoholomorphic: the setwise and global predicates.TauCeti.IsPseudoholomorphicAt.mfderiv_apply_commuteandTauCeti.IsPseudoholomorphicAt.mfderiv_isComplexLinear: the manifold derivative of a pseudoholomorphic map intertwines the two structures, and their within-set analogues.TauCeti.IsPseudoholomorphicAt.comp: pseudoholomorphic maps compose.TauCeti.IsPseudoholomorphicAt.of_comp: a map whose composite with a pseudoholomorphic immersion is pseudoholomorphic is pseudoholomorphic.TauCeti.isPseudoholomorphicAt_neg_neg_iffand its within-set, setwise, and global analogues: reversing both structures changes nothing.TauCeti.isPseudoholomorphicAt_stdComplexLine_iff: for a curve out of the standard complex line the equation reduces to the single coordinate identity∂_t w = J(w) ∂_s w.TauCeti.isPseudoholomorphicAt_iff_isJHolomorphicAtand its within-set, setwise, and global analogues: on model vector spaces the predicate is the normed-space one.TauCeti.isPseudoholomorphicAt_constSmooth_iffand its within-set, setwise, and global analogues: for constant structures on model vector spaces it is the flat, constant-structure predicate.
No regularity beyond the existence of a derivative is imposed: as with the normed-space predicates,
smoothness of u is a separate hypothesis for the results that need it, and taming or compatibility
with a symplectic form is not part of the definition. This keeps the analytic hypotheses unbundled.
The convention follows McDuff--Salamon, J-holomorphic Curves and Symplectic Topology,
Section 2.1: the Cauchy--Riemann equation is du ∘ j = J ∘ du.
A map between almost complex manifolds is pseudoholomorphic within a set at a point when it has a manifold derivative within that set intertwining the source structure at the point with the target structure at the image point.
Instances For
A map between almost complex manifolds is pseudoholomorphic at a point when it has a manifold derivative there intertwining the source structure at the point with the target structure at the image point.
Instances For
A map is pseudoholomorphic on a set when it is pseudoholomorphic within that set at each of its points.
Instances For
A map is pseudoholomorphic when it is pseudoholomorphic at every point.
Instances For
Building and unfolding the predicates #
Build pseudoholomorphicity at a point from a manifold derivative satisfying the pointwise Cauchy--Riemann equation.
Build pseudoholomorphicity within a set from a manifold derivative within that set satisfying the pointwise Cauchy--Riemann equation.
The Cauchy--Riemann equation of the definition says exactly that the derivative is a complex-linear map from the source tangent space at the point to the target tangent space at the image point.
The within-set Cauchy--Riemann equation of the definition says exactly that the derivative within the set is complex-linear.
Restate setwise pseudoholomorphicity as the pointwise within-set condition.
Restate global pseudoholomorphicity as pointwise pseudoholomorphicity everywhere.
The continuous-linear manifold derivative witnessing pseudoholomorphicity at a point.
The chosen manifold derivative at a pseudoholomorphic point is complex-linear.
The continuous-linear manifold derivative witnessing pseudoholomorphicity within a set.
The chosen within-set manifold derivative is complex-linear.
Differentiability and continuity #
A map pseudoholomorphic at a point is differentiable there.
A map pseudoholomorphic within a set at a point is differentiable within that set.
A map pseudoholomorphic at a point is continuous there.
A map pseudoholomorphic within a set at a point is continuous within that set.
A map pseudoholomorphic on a set is differentiable on it.
A map pseudoholomorphic on a set is continuous on it.
A pseudoholomorphic map is differentiable.
A pseudoholomorphic map is continuous.
The Cauchy--Riemann equation for the canonical derivative #
The manifold derivative of a map pseudoholomorphic at a point intertwines the two almost complex structures: this is the nonlinear Cauchy--Riemann equation.
The manifold derivative of a map pseudoholomorphic at a point is complex-linear.
Pseudoholomorphicity at a point is exactly differentiability together with the Cauchy--Riemann equation for the canonical manifold derivative.
The derivative within a set of a map pseudoholomorphic there intertwines the two almost complex structures, provided the set has unique manifold derivatives at the point.
The derivative within a set of a map pseudoholomorphic there is complex-linear, provided the set has unique manifold derivatives at the point.
Relations between the four predicates #
A map pseudoholomorphic at a point is pseudoholomorphic within every set there.
Pseudoholomorphicity within a set that is a neighbourhood of the point upgrades to pseudoholomorphicity at the point.
Pseudoholomorphicity within a set passes to smaller sets.
A map pseudoholomorphic on a set is pseudoholomorphic within that set at each of its points.
A pseudoholomorphic map is pseudoholomorphic at every point.
Pseudoholomorphicity on a set passes to smaller sets.
A pseudoholomorphic map is pseudoholomorphic on every set.
Pseudoholomorphicity within the whole space is pseudoholomorphicity at the point.
Pseudoholomorphicity on the whole space is global pseudoholomorphicity.
The identity, constants, and composition #
The identity map is pseudoholomorphic at every point, for every smooth almost complex structure.
The identity map is pseudoholomorphic within every set at every point.
The identity map is pseudoholomorphic on every set.
The identity map is pseudoholomorphic.
A constant map is pseudoholomorphic at every point, for arbitrary source and target structures.
A constant map is pseudoholomorphic within every set at every point.
A constant map is pseudoholomorphic on every set.
A constant map is pseudoholomorphic.
The composition of pseudoholomorphic maps is pseudoholomorphic at a point: the chain rule for the nonlinear Cauchy--Riemann equation.
A map whose composite with a pseudoholomorphic map of injective differential is pseudoholomorphic is itself pseudoholomorphic: the Cauchy--Riemann equation lifts through an immersion.
The composition of pseudoholomorphic maps is pseudoholomorphic within a set at a point.
The composition of pseudoholomorphic maps is pseudoholomorphic on the source set.
The composition of pseudoholomorphic maps is pseudoholomorphic.
Reversing the structures #
Reversing both almost complex structures preserves pseudoholomorphicity within a set: a map is
(j, J)-holomorphic there exactly when it is (-j, -J)-holomorphic.
Reversing both almost complex structures preserves pseudoholomorphicity: a map is
(j, J)-holomorphic exactly when it is (-j, -J)-holomorphic.
Reversing both almost complex structures preserves pseudoholomorphicity on a set.
Reversing both almost complex structures preserves global pseudoholomorphicity.
Curves from the standard complex line #
A curve from the standard complex line -- that is, ℝ × ℝ with the smooth almost complex
structure SmoothAlmostComplexStructure.product ℝ -- into an almost complex manifold is
pseudoholomorphic at a point exactly when it has a manifold derivative there satisfying the
single coordinate Cauchy--Riemann equation ∂_t w = J(w) ∂_s w. This is the classical form of
the equation for a J-holomorphic curve.
The manifold derivative of a J-holomorphic curve from the standard complex line sends the
imaginary coordinate vector to J applied to the image of the real coordinate vector.
Comparison with the normed-space predicates #
On model vector spaces, pseudoholomorphicity at a point is the varying-structure predicate for maps between normed spaces, applied to the pointwise almost complex structures on the tangent spaces.
On model vector spaces, pseudoholomorphicity within a set at a point is the varying-structure predicate for maps between normed spaces.
On model vector spaces, pseudoholomorphicity on a set is the varying-structure predicate for maps between normed spaces.
On model vector spaces, pseudoholomorphicity is the varying-structure predicate for maps between normed spaces.
For the constant smooth structures of two pointwise almost complex structures on model vector spaces, pseudoholomorphicity at a point is the flat, constant-structure predicate. This is the check that the manifold-level Cauchy--Riemann equation restricts to the linear one.
For the constant smooth structures of two pointwise almost complex structures on model vector spaces, pseudoholomorphicity within a set at a point is the flat, constant-structure predicate.
For the constant smooth structures of two pointwise almost complex structures on model vector spaces, pseudoholomorphicity on a set is the flat, constant-structure predicate.
For the constant smooth structures of two pointwise almost complex structures on model vector spaces, global pseudoholomorphicity is the flat, constant-structure predicate.